The Seattle Longitudinal Study (SLS) has been a major resource for monitoring age and cohort trends in adult cognitive development and for exploring the causes of individual differences in aging. This proposal seeks support for creating a Limited Access Dataset including all cognitive and cognitive style cross-sectional and longitudinal data collected in seven waves from 1956 to 1998. The database contains 9976 complete records involving a total of 4857 study participants. A total of 2,193 participants were followed over 7 years, 1,189 Over 14 years, 662 over 21 years, 381 over 28 years, 158 over 35 years, and 38 over 42 years. Demographic characteristics, such as educational level, occupational status, marital status, mobility characteristics and life satisfaction judgments will be included. A limited public access web site will be maintained until conclusion of the SLS, after which the Dataset will be transferred to a national archive. This application seeks to implement the NIH directives for sharing important databases with the relevant scientific community. The SLS is one of the few studies of cognitive development that covers the entire age range from young adulthood to advanced old age. It is the only such study that contains multiple-cohort data over long age ranges. Data from the SLS have been utilized to predict level and rate of cognitive change across the adult lifespan. Such data have been relevant for discussions of age discrimination in employment and mandatory retirement issues. It is also relevant to the early identification of individuals at risk for dementia in old age many years prior to diagnosis. [unreadable] [unreadable] [unreadable]